Conventionally, in plastic injection molding or non-metallic casting, the film flash which is formed in the flange portion of a casting part is removed by means of just using a punch pin. The film flash may remain as leaned flashes attached to the inside of the flange portion.
The leaned flash can be removed with an abrasive blasting, but the blasting process doesn't have functions that can remove large flashes and collect them because a punching is considered as a process to make a precondition to use a blasting.
Thus if the blasting is used for removing the flashes, an additional manual job is needed periodically to collect the flashes in the blasting cabinet, and then it makes product's cost increased.
There is another means of removing the leaned flashes. The flashes can be removed by designing a diameter of the punch pin almost same as the bore of the flange portion. But, the variation of the bore and the setting location of the casting part cause interference between the punch pin and the flange portion, and the casting part may be scratched and damaged, or the punching process may be stopped with overload.
Some techniques are proposed to solve the above-mentioned problems, for example, utilizing another power source with the punch pin to remove the leaned flashes (referring to JP H08-267350 A or JP 2004-223638 A).
JP H08-267350 A proposes the technique that the flashes are removed manually after automatically removed roughly.
JP 2004-223638 A proposes the technique that the tool portion has a rotating power to remove the flashes, which is independent from the power for the punch pin motion.